1. Field of the Invention
This invention relates to the metal chopping art and, more particularly, to an improved chopper arrangement particularly adapted for chopping insulated transmission lines such as power lines, communication cables, telephone lines, or other metallic-insulated wire or uninsulated wire so as to recover and allow recycling of the metal and of the insulation thereon.
2. Description of the Prior Art
Chopper arrangements of various types have heretofore been utilized for severing material into comparatively short-length segments. However, for many types of materials, such prior art chopper arrangements have not been completely satisfactory. For example, in cutting heterogeneous materials such as transmission lines which may include steel strands which are utilized for strength in the center of the transmission lines and aluminum strands on the exterior thereof for the electrical carrying capacity and such transmission lines covered with insulation, as well as insulated copper electrical transmission lines, prior art chopping arrangements have not always been able to provide a separation of the insulation from the metallic portion of such wire transmission lines and/or have required extensive time for making adjustments to the cutting blades as such blades wear during the cutting operation and/or as different types of material may be fed into the chopper for appropriate cutting.
It is, of course, desirable to recycle as much of the transmission line as possible so that, for example, new aluminum, steel, of copper products may be made from the chopped metal portions of the line and even those portions of the insulation which are reusable, such as certain plastic insulations, may also be salvaged for subsequent use. It is obvious, of course, that the transmission lines that may often be thousands of feet in length and which have been replaced by, for example, higher energy capacity carrying lines cannot be recycled directly in such lengths but first must be severed in to comparative small length segments and, additionally, separated as to material.
For cutting insulated transmission lines into the desired small segments, it is preferred that an exceptionally high impact force be imparted to the transmission line during the chopping action and such high force may be achieved by, for example, a comparatively massive rotor supporting the rotor cutting blades. Such a rotor may, for example, be on the order of 5-7 tons. While the exact mechanism involved is not known, it is believed that the shock and acceleration forces imparted by such a massive rotor in striking the transmission lines to be severed tends to shatter the insulation and imparts a differential acceleration force to the metal parts and to the insulation such that the insulation falls away in small segments from the small segments of the metal portions of the transmission lines. Therefore, chopping can be accomplished in a single pass and not require that severed portions be transmitted to a second, third, etc. stage of chopping as is often required in prior art chopping arrangements.
Additionally, prior art choppers utilized for such purpose as above described have often required extensive down time to adjust the proper positioning of both the rotating cutting blades and the fixed cutting blades. It is recognized, of course, that blades in such a chopper arrangement will wear and require repositioning in order that they may be appropriate material cutting relationship to each other as required for different types of materials being chopped. Because of the comparatively long down time necessitated by prior blade mounting arrangements, the efficiency and chopping capacity per unit time of such prior art choppers has increased the cost per unit weight of the chopped materials.